Carburetor with orifice programming



July 2, 1963 G. E. SELDON CARBURETOR WITH ORIFICE PROGRAMMING Filed Feb. 21, 1958 20'00 .50'00 215M. 'wao United States Patent 3,096,386 CARBURETOR WITH ORIFICE PROGRAMMING George E. Seldon, 534 N. Holmes Ave, Kirkwood, Mo. Filed Feb. 21, 1958, Ser. No. 716,720 8 Claims. (Cl. 261-66) This invention deals with the problem of introducing a mixture of liquid fuel and air into the intake manifold of a heat engine burning oil and air. More specifically, it is concerned with the fuel-air mixing apparatus normally known as a carburetor. A carburetor has an air passage leading to the intake manifold through which the engine aspirates air. The carburetor has a throttle to restrict the flow of fluid through this passage. The air passage has a venturi which is a smooth bore tube with decreasing diameters, the narrowest part or throat of which is near the entrance end. At the narrowest part of the induction tube or venturi the velocity of the passing fluid is the greatest. This velocity is acquired at the expense of static pressure; that is, the static pressure at the throat is depressed below that of the air surrounding the carburetor and is known as the venturi depression. This pressure drop can be measured by means of a manometer or a vacuum gauge. This pressure drop is used largely to push the liquid gasoline out of a reservoir or bowl through a tube leading to the throat of the venturi. The exit of this tube usually projects through the wall of the venturi and ends in an opening known as the jet at the center of the venturi.

In going from low to high speed the engine requires a constantly increasing quantity of fuel-air mixture. The ratio of fuel to air can remain substantially constant over the entire engine range. In practice however, mixtures are usually richer at the lower and top end of the range.

With maximum power the volume of fuel-air mixture aspirated by the engine is substantially proportional to engine r.p.m. throughout the range of speeds. At the top speeds, the demand stops increasing. The venturi depression does not follow proportionately. In terms of inches of mercury or lbs. per square inch virsus engine rpm. venturi depression is a function of the second power of the air velocity through the venturi which velocity is substantially proportional to engine r.p.m. Heretofore the venturi depression was used to move the liquid fuel directly into the air stream in the venturi. Some compensating means sensing manifold pressure depression usually modified or augmented fuel flow at higher speeds.

The improvements shown here also depend on venturi depressions for their operation, but have no mechanically moving parts. They depend rather on orifices in series with the first having means to compensate for necessary Ifuel variables as required for a given engine with its loads. Since the orifices are in series all the vapor passes all but the first orifice, which is set up with means for programming fuel-air mixture quality by sensing quantity of air passing the main passage at the entrance to the venturi. Environmental conditions altering the normal level surface condition or lowering or raising the surface near an air bleed orifice have heretofore influenced the flow characteristics of these orifices tremenduously. Here new methods to control this surface in spite of accelerations. unlevel ground for the vehicle and spillage are shown and solved.

It is an object then to provide a fuel-air induction system for carburetors capable of varying the fuel-air ratio at predetermined points of wide open throttle engine speeds.

It is another object of the invention to provide a carburetor having a main and an auxiliary path for air to enter the carburetor.

It is an object of the invention to provide a carburetor having main and auxiliary air induction paths, with means in the auxiliary air induction path to pick up fuel according to a predetermined schedule.

It is an object of this invention to provide a carburetor capable of delivering to the engine a predetermined schedule of fuel-air mixtures based on full throttle rpm. and said control being accomplished by means of orifices placed in the auxiliary air induction path.

It is an object of this invention to provide a carburetor with an auxiliary passage for mixing fuel and air using relatively large orifices in series to control the mixture flow, and the first orifice having means to vary the ratio of fuel-air mixture according to a predetermined program related to engine fuel demand.

It is an object of this invention to maintain in a carburetor with a mobile reservoir a constant fuel-air ratio and prevent unscheduled changes in the fuel-air ratio due to changes in head between the surface of the fuel and the air metering orifice, caused by loss of fuel splashing over the sides of the reservoir.

It is an object of this invention to maintain in a carburetor with a mobile reservoir a constant fuel-air ratio and prevent unscheduled changes of ratio due to loss of fuel over the sides of the reservoir due to carburetor attitude or accelerations or decelerations in the normal horizontal operating plane.

FIG. 1 is a section through BB of FIG. 2, with an engine.

FIG. 2 is a section through AA of FIG. 1.

FIG. 3 is a view of the fuel-air induction tube, showing the programming air orifice.

FIG. 4 is a section DD of FIG. 3 and shows the depression in the surface of the fuel due to the velocity of air passing through the air orifice.

FIG. 5 shows some curves of pressure drops across the orifices vs. engine r.p.m.

FIG. 6 is view at section CC through the induction tube and its splash shield.

In FIG. 1 air enters the carburetor generally designated as 1 through the opening or mouth 2 of the air horn 50 which has a choke valve 3 which is shown nearly closed which is the position it assumes as the engine is started. This is also the main air induction tube.

After the comparatively large initial diameter of the air horn, the tube fairs smoothly and quickly to the narrowest portion, the throat 4 of the venturi generally indicated as 5. The tube expands again in "skirt 6 as it leaves the throat to match the large diameter of the throttle body 7. A throttle 8 is shown in the closed position in the body 7. The venturi has a flange 9 meeting flange 10 of the throttle body 7 providing the means whereby the parts are bolted together. Similarly flange 11 of the throttle body 7 bolts to flange 12 of the intake manifold 13. The bolts are not novel and not shown. The intake manifold 13 connects to engine 56.

Four small holes approximately Ms" in diameter are equally spaced about the diameter of the throat 4. These small holes 15 are also the main jets through which the extra rich mixture of fuel and air flowing in the auxiliary system is projected into the main stream of pure air in the main air induction tube with which airit mixes to make a combustible mixture. These small holes, orifices 15, connect into an annular passage 16 and through a passage 17 in boss 18 cast onto the air horn 50. A metering tube 19 screws securely into the boss 18 and makes connection with passage 17.

The metering tube 19 has a central bore 20 through the upper narrow portion 49 and the bore connects into the passage 17. A collar 21 on the tube engages the boss 18 and positions the tube. The lower portion of the tube 19 expands into a larger diameter tube 22 with a is lower than the surface '38 of the fuel.

aosasee bore 51. This tube 22 extends downward for some distance as shown. A considerable portion of the expanded part is submerged in the liquid fuel 23 contained in the pan type reservoir 24. The expanded part 22 has a cylindrical baffle 25 riveted to it. A plug 33 with a flat surface 53 is screwed into the boss 18 immediately above the bore 20.

The reservoir 24 is a pan having a cover divided substantially at the center above the trunnions 3h into two parts 26 and 27 and a cylindrical neck 23 at the top connecting both 26 and 27, one (26) of which is higher than the other. The pan has sides 29 to which are welded trunnions 30 which turn in blocks 31 held by arm 32 part of the venturi skirt casting 6. The ends 34 and 35 along with the bottom 36 when properly assembled with the covers 26 and 27, the sides 29 and the neck 28 form a fuel tight reservoir 42 that fulcrums on the trunnions when carrying a quantity of fuel indicated generally by 23 and its top free surface by 38. This surface can indicate a boundary and the free surface of the predetermined quantity of fuel in the pan type reservoir 24-.

The pan cover or ceiling 26 and 27 along with neck 28 prevent the fuel from spilling out of the pan under severe accelerations or decelerations. The top of the neck 28 is placed so that accelerations of fuel Will not be able to spill over it. The point about which the surface turns is the center of gravity of the free surface area. The top edge of the neck 28 then is placed so that the predetermined quantity of fuel with its surface at an angle to the horizontal will not spill over the edge. This is also the device that prevents fuel spillage when the using car is on sloping ground.

The part 26 of the cover or ceiling is higher than the opposite and substantially equal area part 27. The division is above the fulcrums or trunnions 3% and the neck 27 joins both to make the reservoir fuel tight. The reservoir is shown with about the preferred predetermined quantity of fuel in it. It will be seen that the part 27 The inside surface of ceiling 27 is constantly wetted by the fuel. The ceiling 26 on the other hand is much higher and except for occasional splashes or extreme angular displacement, it is not touched by the fuel. Ceiling 27 is also under a slight hydraulic head normally. This is due to the elevation of surface 38 above the lower surface of ceiling 27.

FIG. 2 shows the section AA of FIG. 1 and shows the fuel inlet system which is hidden in FIG. 1. Boss 18 of the air horn extends to the side and houses the inlet port 39 having a female pipe tap 40. A long stemv 41 drops from the boss 18 into the reservoir 24. A bore 43 extends along the center and connects the inlet port 39 to the outlet port and valve seat 44. A valve pin 45 has a conical valve surface 46 that engages seat 44 to control fuel flow through the fuel passage. A depression 47 in the pan bottom 36 engages the pin 45 to locate its lower end. The upper end of the pin cannot fall out of line when the valve is open because of the retainer ring 48.

FIG. 3 shows the metering tube 19 in more detail. It is open at both ends. The wall of the tube 22 defines the opening or port 37 at the bottom through which liquid fuel enters the metering tube 19. An orifice 49 cuts through the wall of the tube 22 to admit air. The top of the orifice 49 is slightly above the surface 38 of the fuel 23. The orifice 49 is long and narrow but is shown wider at the bottom than at the top end. The width X at a given height is a variable and the manufacturer can make it anything he chooses. This Width in relation to height of the opening controls the area of the opening and is the means used to enrich or lean out the fuel-air mixture. The orifice 49 in this figure is shown to cut the bottom rim of the tube 22. This is an arbitrary choice which is subject to needs of the fuel-air ratio and the air i orifice may often be independent of the fuel opening 37, see FIG 1.

FIG. 4 shows a section DD of FIG. 3 and it passes through the center of the air orifice 49. It shows the air stream impinging upon the' fuel surface 38 and pushing the liquid fuel out of its path to enter the orifice 49. The liquid level 52 inside the wide tube 22 rises due to the pressure differential across the orifice 49 and air drawn through the orifice also must pass through the liquid fuel. This air in passing through the liquid shatters the fuel and carries a portion of it through the orifice tube 20.

FIG. 6 shows the bottom view of metering tube 19 and its orifice baffle 25. Here the orifice baflie or splash guard 25 is shown cylindrical and is riveted to the tube on the side opposite the orifice. The baflle need not have much of it submerged in the fuel, 7 should be ample.

Operation The constant level system used here is of the fulcrumed pan type as shown in my Patent No. 2,923,313, As fuel is removed from the pan through the metering tube 19, the level 38 is lowered on the exposed or free surface side (the left side of FIG. 2) of the pan. This side then becomes lighter and the pan turns clockwise about the fulcrum 30. This causes valve pin 45 to move off the seat admitting fuel to supply the quantity being removed or enough to reestablish equilibrium. The pan in rotating, lifts the free surface 38 of the fuel substantially the amount of fuel loss so that the surface 38 remains at almost a constant elevation.

As the engine aspirates air, the primary or main air stream passes the venturi mouth 2, the venturi throat 4, the skirts 5, the throttle body 7 to get to the intake manifold 13, and from there going on into the engine. In passing the throat 4 the passage narrows and the velocity of the air must increase. The force required to increase the velocity of this air is subtracted from the static pressure and the pressure at the throat drops below the pressure of the ambient air. This difference between the ambient and throat pressure is called the venturi pressure depression (V in this application and can be measured in lbs. per sq. inch or inches of mercury.

There is then a pressure differential between the throat and the ambient air pressure around the carburetor and in the reservoir 24 containing the fuel 23. The pressure drop obeys the well known Bernoulli law-- for air to enter the throat 4 of the venturi. This path consists substantially of orifices or main jets 15, the pas sages 16 and 17, bore 20, bore 51, and the orifice 45. This series of tubes, passages, bores, orifices and openings is substantially air tight between the orifices 15 in ,the throat to the orifice 49 in the metering tube 19. The pressure drop across this system is V the same as above, between the throat and the ambient air. In this auxiliary system the air passes three orifices but there could be more or fewer. Starting at the venturi throat there are the orifices 15 and then bore 20 of the metering tube which is also an orifice, and then orifice 49 where the air enters the auxiliary path. The auxiliary air passage is air tight and there is no addition or loss of air or fuel between orifice 49 and orifice 15. All the air passing orifice 49 also passes orifice 2t) and all the orifices 15. A pressure drop exists across each of the three sets of series connected orifices (orifices 15, orifice 2t) and orifice 49 and opening 51), consequently a substantially constant pressure stage exists between each of these series connected sets of orifices.

The air that flows through this auxiliary path to the throat is used to pick up primary fuel and deliver it to the throat. Here the primary fuel mixes with the primary air to become a combustible mixture. Orifices 15 and 20 are fixed in diameter and therefore area, so that any definite quantity of air flowing per unit of time through the system has a predetermined velocity because Q=AV. That is, the quantity flowing per second equals the area of the orifice times the velocity in feet per second. The pressure drop across any orifice is a function of the velocity (across the orifices) squared. For any specific Q the velocity is inversely proportional to the area. Assuming no friction in the auxiliary path and fixed areas of all orifices including orifice 49, initially assume the area of this orifice to be that of the total cut out 49 in the expanded tube 22. Now for small quantities of air flowing, each orifice has its own velocity and corresponding pressure drop. The sum of them equals the venturi pressure depression (V At low venturi pressure drops the small pressure drops across each orifice are a constant percentage of the V and substantially contantly proportional to each other. We have assumed here that orifice 49 is wide open all the time. Orifices 15 and 20 have fixed areas and always have substantially proportional pressure drops across them. Actually the first orifice that air enters, 49, does not present a constant area of opening to the air flowing through it. The perimeter of the orifice 49 is the edges 54 and 55 of the opening and the depressed part 56 of the external surface 38. Indeed when the engine is stopped there is -no air flowing and the surface of the fuel is at 38 and covers most of the gross area, say 95%, of the orifice 49. Assume the engine is now started. Orifices 15 and 20 are fixed and relatively large, so the area of the orifice 49 available to the air is very small. The velocity therefore is very high and the air impinging on the fuel will push the surface fuel from in front of opening 49 and enlarge the area available to the auxiliary air, and Q is constant, since Q=A V, the area increases while the velocity falls off. The pressure drop across orifice 49 will pause the I surface 52 of the liquid fuel to rise above theexternal fuel surface 38 in the bore 51 of tube 22.

The air velocities through orifices 15 and 20 are also inversely proportional to their areas. The pressure drops across each for a specific Q is a predetermined function of each area. Height H is a function of the pressure drop across the available part of orifice 49, 15 plus 20 plus 49 V (see FIG. 5).

The fuel surface 52 inside tube 22. is distance H above the external surface 38 and due to air impinging on the external surface 38 it is pushed down to 56, a distance H below 38. The air then entering through orifice 49 must pass through fuel to a depth of H plus H =H Because this air has high velocity it pushes the fuel out of its way and violently shatters any liquid fuel falling in its path. Some of the fuel is thus picked up by the ,air and carried through the orifice 20. This orifice is long and fuel entering it in drops or slugs is pushed in a single direction along its entire length acquiring considerable velocity. As this slug of liquid fuel leaves the bore 20 with high velocity in the direction of the bore it is thrown across passage 17 and hits the fiat surface 53 of plug or target 33. This causes the drop or slug to shatter and break up still more. Air because of its lower density in leaving the orifice 20 changes its direction much more easily but never the less the air at high velocity carries all the liquid fuel now in finely divided globules or mist along with it and mixes with it. The more liquid fuel in the mixture the richer it is, and the higher the quality is considered to be. The quality of the mixture can be expressed as a ratio of fuelair in lbs.

This mixture then passes through passage 17, and 16 to the main jets or orifices 15 where it enters the venturi at a high velocity 'at right angles to the main air stream passing through the throat 4. This causes the high 6 quality auxiliary air mixture to diffuse with the pure air of the main air stream. The final quality is thus controlled to be a combustible mixture, which mixture then passes on to the intake manifold to the engine.

The method used to control the quality of the final mixture is to properly proportion the areas of the orifices 15-, 20' and 49. More or fewer orifices could be used, but noteall orifices are in series. No fuel or air is added or subtracted between orifices 15 and 49. The area of the 4 orifices 15 are all added together and considered as one orifice. On a standard day (atmospheric pressure and temperature defined) with wide open throttle, a known venturi throat diameter and a known engine displacement; for each r.p.m. rate of the engine there is a predetermined corresponding velocity and therefore quantity Q of air flowing through the venturi throat. This Q increases fairly uniformly with engine rpm. This predetermined velocity causes predetermined venturi pressure drop or V On the chart FIG. 5.

is shown as the highest line. Other lines are also shown set off with proportional ordinates. The distance between the top two lines represents the pressure drop (15 across the 4 orifices 15 and is nominally 5% of V Then the distance the 2nd and 3rd lines from the top represents the pressure drop (20 across orifice 20. The remainder of the distance between line 3 and the zero ordinate represents pressure drop (49 across orifice 49 as though its area were fully available (no fuel coverage). By propontioning the areas of the orifices properly 49 can be made anything required at the maximum r.p.m. of the engine. Lets say this is 0.1 p.s.i., then 0.1 3 =.3" that is the length of slot in 49 that can be uncovered at maximum r.p.m.-=.30". If the orifice 49 area was to be .025" then the average width=.025/.3=.083. Now set the level 38 to cover all orifice 49 except .015". Then the available area is .()l5 .83=.00125" and for any Q, V will be very high. Consequently a relatively large pressure differential will exist here and 52 will be high, H long and the air will pick up more fuel making early mixture quality quite high. The quality could be lowered by raising the orifice or widening it; i.e. add area above the fuel line.

I claim:

1. A carburetor including a main air induction tube to induce primary air, said tube having a venturi with a throat with main jets there-in; a self-contained fuel reservoir having trunnions mounting it upon the carburetor for swinging movements; means operated by such swinging movements of the reservoir for establishing and maintaining a definite quantity of liquid fuel there-in, establishing a specific fuel level in said reservoir, an auxiliary induction tube supported on the carburetor to remove a rich mixture of primary fuel and auxiliary air from said reservoir and deliver it to said throat, the outlet end of said auxiliary tube connected into the main jets in the throat of said venturi, the fuel inlet port being the open opposite end of said auxiliary tube and submerged deep in said definite quantity of liquid fuel, said tube piercing the surface of said quantity of fuel held in said selfcontained reservoir within the bounds there-of and near the center of said definite quantity of fuel in said reservoir; the axis of the trunnions being transverse to the axis of the tube and close thereto; a slot out through the wall of said auxiliary tube and part of said slot above the surface level of said fuel and the remainder below, where-by said engine aspirates a mixture of air and primary fuel through said auxiliary induction tube, the air being-admitted through that part of the slot above the fuel level and the primary fuel admitted through the lower part of the slot below the fuel level and the port at the bottom of said auxiliary induction tube.

2. A carburetor including a main air induction tube 7 to induce primary air, said tube having a venturi with a throat with main jets therein; a fuel reservoir containing a quantity of liquid fuel; an auxiliary induction tube to convey a rich mixture of primary fuel and auxiliary air from said reservoir to said throat, the outlet of said auxiliary tube connected into the main jets in the throat of said venturi, the fuel inlet port including the open opposite end of said auxiliary tube and submerged deep in the liquid fuel in the reservoir; 21 slot cut through the Wall of said auxiliary induction tube and part of said slot above the surface of the fuel and the remainder below, whereby said engine aspirates a mixture of air through said main induction tube plus auxiliary air and primary fuel through said auxiliary induction tube, said auxiliary air being admitted through that part of the slot above the surface of said fuel and the primary fuel admitted through that part of the slot below the fuel surface and the opening at the bottom of said auxiliary induction tube, said carburetor having a splash guard encircling the auxiliary tube in the vicinity of the combination fuel-air inlet slot to limit the effect of liquid surface motion on the flow characteristics of said slot.

3. For an engine burning a liquid fuel-air mixture, a carburetor having a main air passage including a venturi with a throat and main jets therein; a liquid fuel reservoir containing a quantity of fuel; an auxiliary tube for carrying a high quality fuel-air mixture, the outlet end of said tube connected into the main jets at the throat of said venturi, the inlet end of said tube having a relatively large diameter and projecting deep into the liquid fuel in said reservoir, an orifice in the form of a slot cut in the side of the large diameter tube, said slot partly above the surface of the fuel and partly below, whereby on aspiration by said engine a mixture of air and fuel is drawn through said slot and delivered to said engine through the main jets in the throat of said venturi, and the outlet end of said auxiliary tube being a tube of small diameter and of considerable length through which the fuel-air mixture passes and solid globules of fuel carried here by the passing fuel-air mixture accelerate in the direction of the air passage and a target just beyond the outlet in the path of said globules, whereon said globules are thrown, fragmentized, and carried along with the mixture to the throat of the venturi and on to said engine.

4. In an oilburning variable speed heat engine; for mixing liquid fuel and air a carburetor having a venturi shaped maininduction tube with a narrow throat through which said engine aspirates air, main fuel jets ported into said main induction tube at said throat; said carburetor including a self-contained reservoir having tnunnions mounting the reservoir onto the carburetor and about which the reservoir may swing, means for storing therein a body of fuel having a definite mass, a free level surface on said body established at a fixed elevation in said reservoir; means for adding fuel as removed from said reservoir, said means being actuated by the rocking of the reservoir about its trunnions; for removing fuel from said reservoir an auxiliary fuel-air induction tube having its outlet connected into said main fuel jets, and the inlet of said auxiliary tube projecting deep into said body of fuel and passing near the center of gravity thereof, a slotted orifice in the side of said auxiliary induction tube, part of which slot is covered by fuel and a small part remaining open to the air above said free surface, whereby fuel and air may be removed from said reservoir and delivered to said jets in said main induction tube; and whereby said engine on aspirating air through said main induction tube creates a pressure drop across the length of said auxiliary tube, a series of restricting orifices in said auxiliary tube whereby the total pressure drop is divided into a corresponding series of steps, the first restricting orifice being the small part of said slot above said fuel surface, which fuel surface in said orifice moves downward in said orifice with increasing air velocities through that part above the fuel surface whereby the area of said first air orifice 'varies according to the velocity of air flowing therethrough.

-5 In a'carburetor for a heat engine burning a liquid fuel-air mixture; a main air induction tube including a throat with main jets there-in; a self-contained reservoir with mounting trunnions supporting the reservoir for rocking movement on the carburetor for storing liquid fuel; a finite quantity of fuel in said reservoir, said quantity of fuel having a free upper surface establishing a fuel level at a definite elevation with respect to said trunnions and the rest of the carburetor; constant level mechanism for replenishing fuel as removed from said reservoir to maintain the quantity of fuel at said finite value and the level at said constant elevation in said reservoir; to remove fuel and air in the form of a high quality fuel-air mixture from said reservoir and deliver it to said main jets an auxiliary tube, the outlet end of said tube connected into said jets, the inlet and opposite end plunged deep into said quantity of fuel in said selfcontained reservoir, the inlet end of said tube within the confines of said self-contained reservoir, said tube passing near the center of said quantity of fuel and the tube being transverse to the trunnion axis and its axis being close to the trunnion axis, a fuel port at the inlet end of said tube also an opening cut through the wall of said tube forming a combined fuel-air orifice, which orifice is partly covered by fuel below said free surface, whereby \a high quality mixture of liquid fuel and air is aspirated through said auxiliary tube and said jets into said venturi to mix with the primary air aspirated there-through by said engine, thereby supplying a combustible fuel-air mixture for said engine; and a restrictor in said auxiliary tube between said slotted orifice and said main jets to control the flow rate of the rich mixture through said auxiliary tube.

6. In a vehicular carburtor; a venturi; a self-contained mobile reservoir having trunnions on a common axis about which said reservoir may turn relative to said carburetor; a predetermined quantity of liquid fuel in said reservoir providing a free unconstrained upper fuel surface in said reservoir at a fixed elevation relative to said axis; fuel tubes attached to said carburetor, one tube with a control valve to admit fuel into said reservoir, a second tube to remove fuel from said reservoir and deliver it to said venturi; means whereby the turning of said reservoir about said axis actuates said control valve to admit fuel into said mobile reservoir to maintain said free surface at said elevation regardless of fuel removed there-from; on said mobile reservoir to one side of said axis a submerged ceiling covering part there-of, said ceiling displacing some fuel so that the free fuel surface lies to the side of said axis opposite and above said submerged ceiling; and a fuel tight cover over the remainder of said reservoir at an elevation above said free surface r so that in operation of said vehicle said cover remains unwetted by fuel except for splashing and extrem; angular displacements of said vehicle and carburetor; an

opening in said cover substantially above said axis "to give said fuel tubes access to said fuel in said self-contained mobile reservoir, without interference between" said self-contained mobile reservoir and said fixed tubes and other parts of said carburetor, on act-nation of said control valve, by the turning of said self-contained reservoir about said axis.

7. In a vehicular carburetor; rigidly fixed there-to a fuel outlet tube and a fuel inlet tube with a control valve; constant level mechanism including a self-contained mobile reservoir with trunnions on a common axis about which said reservoir may rotate with respect to said carburetor and said fixed tubes; a predetermined quantity of fuel with a free unconstrained surf-ace in said reservoir; means for actuating said valve by the rotation of said reservoir about said axis whereby said valve is actuated to maintain said predetermined quantity of fuel in said reservoir regardless of fuel removal; on said self-contained reservoir a fuel tight cover having a portion so placed above said free surface as to be unwetted by fuel during the normal operation of said vehicle, and said carburetor except for splashing and extreme angular displacements of said vehicle and said carburetor and said cover having another portion below the normal upper surface levels of the liquid so that the quantity of liquid thereunder remains constant throughout operation of the carburetor, said cover over all of said reservoir except an opening in about the center of said cover over said axis to permit said fuel tubes access to said fuel, a continuous collar circumscribing said open ing making a fuel tight connection there-with, said collar extending upwardly to such a height above said free fuel surface that all the fuel remains in said reservoir even though the carburetor is horizontally accelerated, and said opening and said collar so sized and placed relative to said tubes as to permit operation of said valve by the rotation of said mobile reservoir without interference there-0f with the fixed parts of said carburetor.

8. In a vehicular carburetor; rigidly fixed there-to a fuel outlet tube and a fuel inlet tube with a control valve; constant level mechanism including a self-contained mobile reservoir with trunnions on a common axis about which said reservoir may rotate with respect to said carburetor and said fixed tubes; a predetermined quantity of fuel with a free unconstrained surface in said reservoir; means for actuating said valve by the rotation of said reservoir about said axis whereby said valve is actuated to maintain said predetermined quantity of fuel in said reservoir regardless of fuel removal; on said selfcontained reservoir a fuel tight cover so placed above said free surface as to be unwetted by fuel during the normal operation of said vehicle, and said carburetor except for splashing and extreme angular displacements of said vehicle and said carburetor, said cover over all of said reservoir except an opening in about the center of said cover over said axis to permit said fuel tubes access to said fuel, a continuous collar circumscribing said opening making a fuel tight connection there-with, said collar extending upwardly to such a height above said free fuel surface that all the fuel remains in said reservoir even though the carburetor is tilted from the horizontal and said opening and said collar so sized and placed relative to said tubes as to permit operation of said valve by the rotation of said mobile reservoir without interference there-of with the fixed parts of said carburetor.

References Cited in the file of this patent UNITED STATES PATENTS 1,642,332 Carlsson Sept. 13, 1927 1,795,898 Schneider Mar. 10, 1931 2,419,956 Kuzellea May 6, 1947 2,790,633 Seldon Apr. 30, 1957 2,923,313 Seldon Feb. 2, 1960 2,996,289 Seldon Aug. 15, 1961 

1. A CARBURETOR INCLUDING A MAIN AIR INDUCTION TUBE TO INDUCE PRIMARY AIR, SAID TUBE HAVING A VENTURI WITH A THROAT WITH MAIN JETS THERE-IN; A SELF-CONTAINED FUEL RESERVOIR HAVING TRUNNIONS MOUNTING IT UPON THE CARBURETOR FOR SWINGING MOVEMENTS; MEANS OPERATED BY SUCH SWINGING MOVEMENTS OF THE RESERVOIR FOR ESTABLISHING AND MAINTAINING A DEFINITE QUANTITY OF LIQUID FUEL THERE-IN; ESTABLISHING A SPECIFIC FUEL LEVEL IN SAID RESERVOIR, AN AUXIALLY INDUCTION TUBE SUPPORTED ON THE CARBURETOR TO REMOVE A RICH MIXTURE OF PRIMARY FUEL AND AUXIALLARY AIR FROM SAID RESERVOIR AND DELIVER IT TO SAID THROAT, THE OUTLET END OF SAID AUXIALIARY TUBE CONNECTED INTO THE MAIN JETS IN THE THROAT OF SAID VENTURI, THE FUEL INLET PORT BEING THE OPEN OPPOSITE END OF SAID AUXIALIARY TUBE AND SUBMERGED DEEP IN SAID DEFINITE QUANTITY OF LIQUID FUEL, SAID TUBE PIERCING 